The volume of the milk in the measuring cup does not change when it is transferred to the mixing bowl.
Volume is the amount of space a body or substance occupies.
It is determined by the amount of matter that is present within a given measurement.
Since the amount of milk was accurately measured out, the volume is maintained when it is transferred to the mixing bowl. The reason why a measuring cup is used is to keep the consistency of the measurement.
Both John Dalton and Democritus thought that the atom was an indivisible sphere until J.J. Thompson came out with the plum pudding model. Hope I helped!